U.S. patent number 4,677,187 [Application Number 06/866,417] was granted by the patent office on 1987-06-30 for furfuryl alcohol-aldehyde resins.
This patent grant is currently assigned to Acme Resin Corporation. Invention is credited to David R. Armbruster, Merlyn Pasion.
United States Patent |
4,677,187 |
Armbruster , et al. |
June 30, 1987 |
Furfuryl alcohol-aldehyde resins
Abstract
Furfuryl alcohol-formaldehyde resins which can be prepared by
using a water soluble multivalent metal salt as the catalyst,
thereby eliminating the use of an acid catalyst and the necessary
attention it requires.
Inventors: |
Armbruster; David R. (Forest
Park, IL), Pasion; Merlyn (Chicago, IL) |
Assignee: |
Acme Resin Corporation
(Westchester, IL)
|
Family
ID: |
25347568 |
Appl.
No.: |
06/866,417 |
Filed: |
May 23, 1986 |
Current U.S.
Class: |
528/232; 524/593;
524/598; 528/233; 528/235; 528/237 |
Current CPC
Class: |
C08G
16/0262 (20130101) |
Current International
Class: |
C08G
16/00 (20060101); C08G 16/02 (20060101); C08G
004/00 () |
Field of
Search: |
;524/593,598
;528/232,233,235,237 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Phynes; Lucille M.
Claims
What is claimed is:
1. A process for preparing furfuryl alcohol-aldehyde resins
comprising:
reacting under hydrous conditions:
(a) an aldehyde of the formula R--CHO, wherein R is hydrogen or a
hydrocarbon radical containing about one to eight carbon atoms;
and
(b) a furfuryl alcohol or a substituted furfuryl alcohol compound
having the formula: ##STR2## wherein R.sub.1 can be an alkyl, aryl,
alkenyl, alkylol, alkoxy, aryloxy, halogen or hydroxy radical, and
mixtures thereof; said reaction being conducted in the presence of
a catalytic amount of a water soluble multivalent metal salt
wherein a sufficient amount of catalyst is present in aqueous
solution to adequately catalyze said reaction.
2. The process of claim 1, wherein said catalyst is selected from
the group consisting of zinc acetate, lead acetate, and mixtures
thereof.
3. The process of claim 1, wherein the aldehyde is
formaldehyde.
4. The process of claim 3, wherein the formaldehyde is
formalin.
5. The process of claim 1, wherein the furfuryl derivative is
furfuryl alcohol.
6. The process of claim 5, wherein the mole ratio of furfuryl
alcohol to aldehyde can vary from about 3:1 to about 0.5:1,
respectively.
7. The process of claim 6, wherein the amount of catalyst varies
from about 0.2 to 8% by weight of furfuryl alcohol.
8. The process of claim 1, wherein the reaction temperature varies
from about 85.degree. to 105.degree. C.
9. The process of claim 1, wherein the reaction is carried out at
elevated pressure sufficient to prevent the reaction mixture from
boiling and the temperature varies from about 105.degree. C. to
140.degree. C.
10. The process of claim 1, wherein the metal moiety of the water
soluble multivalent metal salt is selected from the group
consisting of Mn, Zn, Cd, Mg, Co, Ni, Fe, Pb, Ca, Cu, Sn, and
mixtures thereof.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to furfuryl alcohol-formaldehyde
resins which are useful as foundry binder compositions, and as
laminating, coating and bonding resins.
2. Description of the Prior Art
Furfuryl alcohol-formaldehyde resins are well known in the art and
have been of commercial importance for many years. These resins are
generally made by using an acid catalyst to catalyze the reaction
of formaldehyde with furfuryl alcohol, or by reacting furfuryl
alcohol with itself or a combination of these two reactions.
The use of an acid catalyst in forming furfuryl
alcohol-formaldehyde resins requires a substantial amount of
attention to control the acid pH of this reaction. If the pH
becomes too low, the furfuryl alcohol may self-polymerize at a rate
that could lead to a runaway reaction.
SUMMARY OF THE INVENTION
The present invention relates to furfuryl alcohol-formaldehyde
resins which can be prepared by using a water soluble multivalent
metal salt as the catalyst, thereby eliminating the use of an acid
catalyst and the necessary attention it requires.
DESCRIPTION OF THE PREFERRD EMBODIMENTS
In accordance with the present invention, furfuryl
alcohol-formaldehyde resins are produced in a process which
incorporates a water soluble multivalent metal salt as the
catalyst. The use of a water soluble multivalent metal salt
eliminates the necessity of using a protonic acid catalyst and the
reaction is carried out under essentially hydrous conditions.
The preferred source of formaldehyde is 50% formalin. However,
other grades can be used. Paraformaldehyde can also be used if
sufficient water is added to the reaction to maintain all or a
substantial portion of the catalys in solution.
Furfuryl alcohol, formaldehyde and the multivalent metal salt
catalyst are simply added to a reaction vessel and heated to
reaction temperature.
The water soluble multivalent metal salt catalysts which can be
used in this reaction include the multivalent ions of manganese,
zinc, cadmium, magnesium, cobalt, nickel, copper, tin, iron, lead
and calcium. Preferred catalysts are zinc acetate, lead acetate or
mixtures thereof.
In the reaction of furfuryl alcohol, formalin and the multivalent
metal salt catalyst, it is desirable to remove excess water from
the condensation reaction and water present in formalin in excess
of the amount necessary to solubilize the catalyst. The water
removal can be accomplished by distillation during the reaction and
increases the rate of reaction as well as reduce the water content
of the final product. Water removal can be accomplished
conveniently during the reaction or at any point which facilitates
processing of the product.
An important constraint on the amount of water removed during the
reaction is that sufficient water be present to maintain enough
multivalent metal salt in aqueous solution to catalyze the reaction
between the furfuryl alcohol and formaldehyde. Undissolved catalyst
is not useful to catalyze the reaction. Therefore, an adequate
amount of catalyst should be present in aqueous solution to
catalyze the reaction.
The mole ratio of furfuryl alcohol to formaldehyde can vary from
about 3:1 to about 0.5:1, respectively, preferably about 2:1 to
1:1.
The amount of water soluble multivalent metal salt used as the
catalyst can vary from about 0.2 to about 8% by weight of the
furfuryl alcohol.
The inventive reaction can be carried out at temperatures of about
85 to 105.degree. C. at atmospheric pressure or at elevated
temperatures under pressure. One of the primary concern in carrying
out the reaction at elevated temperatures and pressures is to
prevent the reaction mixture from boiling. Thus, for example, if an
operating temperature of 140.degree. C. were desired, the pressure
must be correspondingly elevated to prevent the reaction mixture
from boiling.
The end point of the reaction can be controlled by reacting to a
free formaldehyde level or to a viscosity specification. The final
product can be used as is or diluted with a suitable solvent,
including furfuryl alcohol or water.
Although the reaction has been described in terms of formaldehyde,
other aldehydes of the general formula: R--CHO can also be used,
wherein R is a hydrocarbon radical containing about 1-8 carbon
atoms such as formaldehyde, acetaldehyde, propionaldehyde,
furfuraldehyde, and the like. The preferred form of formaldehyde is
in the hydrous state, such as formalin.
Furfuryl alcohol or substituted furfuryl alcohol compounds can be
used with the formula: ##STR1## where R.sub.1 can be an alkyl,
aryl, alkenyl, alkylol, alkoxy, aryloxy, halogen or hydroxy
radical. The preferred compound is furfuryl alcohol.
The examples which follow serve to illustrate the present
invention, and all parts and percentages are by weight unless
otherwise indicated.
EXAMPLE 1
Into a 5 liter 3 necked flask equipped with a stirrer, thermometer,
and reflux condensor were charged 2000 grams of furfuryl alcohol,
1000 grams of 50% formalin and 80 grams of a 25% water solution of
zinc acetate. Heat was applied to the flask and the contents
reacted for 3 hours at a temperature of 95.degree.-97.degree. C.
The reaction mixture was then cooled by dehydration and dehydrated
at about 50.degree. C. to remove 590 grams of distillate. The
reaction was then continued for 20 hours and 55 minutes at
97.degree.-98.degree. C. with steam heat. At this time, the free
formaldehyde level had dropped to 3.2% and the batch was cooled by
applying cooling water to the flask. The product had viscosity of
1690 centipoise at 25.degree. C. 50 grams of water were added to
reduce the viscosity to 1115 centipoise. The final product had
15.5% unreacted furfuryl alcohol and 6.4 % water.
EXAMPLE 2
Into a 5 liter 3 necked flask equipped with a stirrer, thermometer,
and reflux condenser were charged 2000 grams of furfuryl alcohol,
700 grams of 50% formalin and 50 grams of a 25% water solution of
zinc acetate. Heat was applied to the flask and the contents
reacted for 1 hour and 20 minutes at 95.degree. C. to 97.degree. C.
At this time an additional 600 grams of 50% formalin and 40 grams
of 25% zinc acetate solution were added and the reaction continued
for an additional 1 hour and 30 minutes at 95.degree. C. to
97.degree. C. The contents of the flask were then cooled to
70.degree. C. and vacuum dehydrated at this temperature until the
batch turned from clear to slightly hazy. The haziness indicated
that a small portion of the catalyst had become insoluble at this
temperature. 2596 grams of reaction product along with unreacted
materials remained in the flask at this time. The batch was then
heated to 95.degree. C. to 97.degree. C. and reacted for 16 hours
and 45 minutes before cooling to give a final product with a
viscosity of 1,490 cps at 25.degree. C. containing 10.7% unreacted
furfuryl alcohol and 5.2% unreacted formaldehyde.
* * * * *